Beginner needs some ideas how to draw/design this:

I am trying to create a grid-pattern (thijn black horizontal and vertical
lines) on a rectangular wooden surface (like a table top). The grid-pattern
doesn't fill the surface completly, the surface has a empty (no grid lines)
border area. As an additional challenge I want to create the impression that
the surface area is one solid block of wood, meaning you should be able to
follow grain lines across the complete surface

I can see multiple waysdoing this:
(1) It is fairly easy to design this 'peacemeal' by using boxes for the the
black lines and fill the area between the lines with wooden textured boxes
and draw the border area separatly around the the complete thing.
Disadvantage: I don't think it will create the "one solid peace of wood
feeling"

(2) I could create a wooden box and use layered textures (I guess) to create
the grid pattern. I still need to create the boarders peacemeal ... same
disadvantage as (1) I guess, it will probably look like I glued the sides to
the 'grid box'

(3) This is the thing I actually tried: I created the wooden surface (the
table top) and created the grid lines as boxes which are 'just a little bit'
over the surface. This creates initially good results (with a nice 'solid'
tabletop) and nice looking grid line, but if I increase camera distance to
the table the lines get very 'spotty', probably because the minimum
evaluation of the grid over the surface is just an appoximation, and
rounding problems mess things up (my theory)

I am currently thinking of giving up on my 'solid wood' requirement (with
increased camera distance it will be hard to see the benefit of it) and go
with proposal (1) or (2).

Questions:
- any other ideas how to solve this ?
- which idea makes more sense in respect to POV: more objects (as in 1) or
more complex textures (as in 2)


Thanks
Wolfgang

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In article <39ab320d$1@news.povray.org>, "Wolfgang Manousek" 
<wol### [at] to_much_spamcom> wrote:

> (3) This is the thing I actually tried: I created the wooden surface 
> (the table top) and created the grid lines as boxes which are 'just a 
> little bit' over the surface. This creates initially good results 
> (with a nice 'solid' tabletop) and nice looking grid line, but if I 
> increase camera distance to the table the lines get very 'spotty', 
> probably because the minimum evaluation of the grid over the surface 
> is just an appoximation, and rounding problems mess things up (my 
> theory)

If you mean you get dots along the line instead of a solid line, that is 
due to the fact that pixels are represented as points, not as squares. 
This isn't exactly a precision problem, your details are just too small 
to be represented at the resolution you are rendering at. You can use 
anti-aliasing to smooth things out(it basically calculates several 
samples over the area of each pixel), but your lines may disappear at 
lower resolutions. Textures will have the same problem, it isn't due to 
your using an object.

Either boxes or a layered texture should work, and it should be possible 
to get a pigment_map in your texture that only applies the lines where 
you want them. There are some features in MegaPOV that can make this a 
lot easier, but it should be quite possible in ordinary POV.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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most of your assumptions are incorrect.  let's go through each...

Wolfgang Manousek wrote:
> 
> Beginner needs some ideas how to draw/design this:
> 
> I am trying to create a grid-pattern (thijn black horizontal and vertical
> lines) on a rectangular wooden surface (like a table top). The grid-pattern
> doesn't fill the surface completly, the surface has a empty (no grid lines)
> border area. As an additional challenge I want to create the impression that
> the surface area is one solid block of wood, meaning you should be able to
> follow grain lines across the complete surface
> 
> I can see multiple waysdoing this:
> (1) It is fairly easy to design this 'peacemeal' by using boxes for the the
> black lines and fill the area between the lines with wooden textured boxes
> and draw the border area separatly around the the complete thing.
> Disadvantage: I don't think it will create the "one solid peace of wood
> feeling"

if a top level csg item (your table) is given a single texture, then it
will look like one solid piece.  you could still include black-textured
boxes inside that csg and get the same solid wood look, but with the
lines you want.

 
> (2) I could create a wooden box and use layered textures (I guess) to create
> the grid pattern. I still need to create the boarders peacemeal ... same
> disadvantage as (1) I guess, it will probably look like I glued the sides to
> the 'grid box'

you can use a texture on one solid box to get the effect you are looking
for.  someone has done very good tutorials placing stars and other
geometric shapes precisely on spheres using only povray textures.  i,
myself did all of the variously shaped blue areas on r2d2's head using
what i learned from that tutorial.  perhaps this is more difficult than
number one above.
 
> (3) This is the thing I actually tried: I created the wooden surface (the
> table top) and created the grid lines as boxes which are 'just a little bit'
> over the surface. This creates initially good results (with a nice 'solid'
> tabletop) and nice looking grid line, but if I increase camera distance to
> the table the lines get very 'spotty', probably because the minimum
> evaluation of the grid over the surface is just an appoximation, and
> rounding problems mess things up (my theory)
> 
> I am currently thinking of giving up on my 'solid wood' requirement (with
> increased camera distance it will be hard to see the benefit of it) and go
> with proposal (1) or (2).

i agree with the other post as to why increased distance made it look
spotty.  you need a larger image with anti-aliasing on.  another
technique you could use is to make a grid of cylinders, give them a
black texture, and use the bottom 180 degrees to cutout lines in the
table.  this is more of a design change than a way to get what you want,
but i think it would look good.  i hope you aren't trying to make a
chess board as nearly every one is not made of a solid piece of wood.

                /-\ <-cylinder used for cut
---------------|   |-------------- <-wood level
                \-/  

 
> Questions:
> - any other ideas how to solve this ?
> - which idea makes more sense in respect to POV: more objects (as in 1) or
> more complex textures (as in 2)
> 
> Thanks
> Wolfgang

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Thanks for the advice from everyone ... looks like I have to look more into
textures ...

Wolfgang:

PS: no - it is not a chess board ;-)

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Wolfgang Manousek <wol### [at] to_much_spamcom> wrote:
> Thanks for the advice from everyone ... looks like I have to look more into
> textures ...

> Wolfgang:

> PS: no - it is not a chess board ;-)

Sounded like a classical go board with a border to me...

Geoff

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